Tkansfobmeb fob open ahb closed signal systems



TRANSFORHER FOR OPEN AND CLOSED SIGNAL SYSTEMS 4 Filed 00's. 21. 1926 L L@ l I /0 j.

/.0^ c j /V c es E 6 4 Inventar..

A Uf//l'aqy EZdtr l v A4) I /J M 62%/ @may Patented Oct. 18, 1927.

WILLIAM F.. LEATHER,

or cercano, ILLINOIS.

TRANSFORIYIER FOR GEEN ANDCLOSED SIGNALMSYSTEMS.

application filed october 21, isere. serian Nauen/v] My invention relates to transformers, and in its general objects, my inventionaims to provide an inexpensive and easily constructed transformer which can be used interchangeably on normally open circuits, normally closed circuits, or on combinations of normally open and normally closed circuits, and which can be operated on a closed circuit for long periods of time with no pereep' tible heating.

More particularly, my invention provides. a transformer adapted to be connected to anv ordinary alternating current. lighting circuit (such as the commonly used 110 volt circuit) for furnishing current intermittently at low voltages to an electric bell or an audible sigv nal, and for also supplying current continuously to a burglarV armcircuit, toy train or the like.

In one of its immediate commercial appli-V cations, the transformer of my invention is particularly suited for use in a burglar alarm system in which an interruption of a normally closed circuit actuates a switch so as to close the normally open circuit to a bell or other electrically operated signal device. I-Ience'I am illustrating and describing my transformer as employed for such apurpose, though I do not wish to be limited to any 3c particular use of my invention. f In the drawings, Y y Fig. l is a perspectiveview of a combined open circuit and closed circuit. transformer embodying my invention, Y

Fig. 2 is a. side elevation` of the two transformer cores, also showing the dielectric which is desirably interposed between the main core and the auxiliary core.

Fig. l3 is an elevation of. one of the major 4" parts of the laminated main core. p y

Fig.` 4 is an elevation of one of the `supplemental strip parts of the main core.

Fig. 5 is an elevation of one of the laminations of the auxiliary end core.

Fig. 6 is a diagram showing the connections of the transformer windings in a burglar alarm system in which a trip is operated by the interruption of a normally closed circuit, and in which the actuation of this 5l trip closes anormally open bell circuit.

Fig. 7 is a somewhat diagrammatichortl zontal section through my transformer as employed in the system. of 6, .showing how the several windings are respectively.V

vmally closed circuit.

connected to the source of current-supply,v the relay or trip` device, and the signal bell.'

Referring first to the diagram of Fig. 6, this includes a transformer iny which the main inductance winding l, fed from a 110 volt supply circuit, is in inductive relation to a secondary winding 2 and also to an aux! iliary winding 3. The secondary winding 2 is in serieslwith a circuit which includes bothv anelectric b'ell't and a normally open switch, the switch beingv shown as includinga sta tionary contact 5 and a pivoted switch arml 6, which switch arm is. normally held' above and out of engagement with the contact 5 by -a detent arm 7v carried by a pivoted armature 8,(so ythat open. l

,The auxiliary winding 3 is in series with an interrupter 9, which may be of any type commonly employed in closed circuit fb'urglar alarm systems, so as to aifordga nor-V y This `interrupter is shunted by a circuit 10V through an electrothe bell'circuit is normally magnet 1,1 which is disposed for' lifting the f armature 8 whencurrent flows through the electromagnet, butthe winding ofthe Llatter is of such resistance that no appreciable i current flowsl through it unless the interrupter 9 is actuated. When the normally closed circuit Vthrough the interrupter 9 is ruptured, the current induced in the transformer winding 3 flows through theshunt circuit 10 and causes the electromagnet 11 to raise thearmature 8, thereby-releasing the; detent 7 and permitting the switch arm `6 to close the circuitto the bell 4, so that the bell will ring continuously until the switch arm is manually returned to its i detent` latohed position.

I n operating such an alarm system, it is necessary to have both an `available supplyof current for the electric Vbell (or other equivalent alarm signal) and a supplyof current for the closed circuit'throughV the` burglar-actuated interrupter. The voltages` suitablefor these two. currents may varyA according to the size ofthe bell (or other alarm device) and according tothe lengthsA -of the respective circuits. important that the continuous flow of ycurrent through `the circuit leading to the in-p,

terrupter 9 (orto a plurality of such rupe turable elements arranged in series the customary in closed circuit burglar Moreover, it is alarm systems) will not cause any consider able heating ofl the transformer, p t

To meet these conditions and to obtain current for all parts of the system 'from a single unit, I construct my transformer with two cores disposed so that the main` core alords a closed magnetic circuitthrough both the supply (or main) winding and the secondary (bell circuit) winding` which is normally open, while the auxiliary core cooperates with the main core in. affording` a partly open magnet-ic circuit disposed in effective relation tothe auxiliary (or detentactuating) windingv and designed for radiating any generated heat.

For this purpose, Figs. 1 to 4 show the main transformer' core as builtot laminations eaehof which comprises .a major part shaped'like a letter E turned on one side, anda supplemental part in the form of a strip `disposed in edgewise engagement with the ends of the three parallel arm portions of the Vsaid letter E. These laminations are alternately turned with the back of the E at the bottom and at the top, as shown at 13 in Figs., 2 and 3, yand with the supplemental strips 14 alternately at the top and the bottomwof the core, and the assembled laminations Vare secured to each other by bolts. 15. Thus assemblechthe main core is of a form sometimes employed in shell type transformers. Y Y

For the auxiliary core, T employ laminations` 16 each punched like asletter E, with the arms desirably of length equal tothe total height of the main core portion. l-low-v ever, these laminations le may be smaller in teach of their other dimensions as less space is needed between their arms for por-1 tions of windings, and the total'thickness ot" the ai Xiliary core `portion may be considerahly lessv than that ot the main core portion. These lainiiiationsl desirably all have their' armsextend inthe same direction, as shownl in, l, and aresuitaloly secured to each" the'ryas forY exampleby rivets 17.` c

I auxiliary corefis disposed at right, ancles' to vthe main core., with its centralE stem 13a extending parallel tone lateral stem, ofthe main .core but spaced from the' latter stem by a dielectricv 18. Thusassembled', the'tWo'COres'are employed in connee n Ywitlhifl an inner primary winding' 1, a se'cordarywinding 2 surrounding the wint ing;1,`a' nda thirdwinding` 3 which is superposed at1 one sidel oiifthe secondary winding 2f and which passes around the outer tace ofthe medialj stem ol the auxiliary core. Thus'arrahgechtlie main core and the'wind ings 1 and 2' constitutea' shell Itype transforiiiei, and the"winding` 3 is an additional winding which l have found highly suitable'- fdr'vuseon a closed circuit. To allow for thif thirdA winding Without materially re-V dingfthe eiiieieney' of the shelltype transL former portion, I make the space A between the medial shankot the main core and the side shank 13b adjacent to the auxilia core `iust wide enough to receive the superposed primary and secondary windings 1 and :2. Then l make the space B between the medial shank and the other shank 13c of the main core sufficiently wid-er than the space A to accommodate the third winding 3 also.

ln manufacturingsuch a transformer, the two inner windinfrsvnamely the supply current or main winding 1 and the open circuit winding' 2 can readily be wound on a suitable spooll or mandrel and secured to each other to 'form a hollow unit. Likewise, the closed circuit coil 3 can be preformed vand slipped yover the said'ho'llow unit, andthe entire auxiliary core can be assembled as a separate unit. Then the main core canpbe assembled'by slipping` itsv consecutive'rlamid nation portions into place respectively from opposite en dsot the said hollowunihjand boltingr the parts of the assembled'core toygather, after which the auxiliary core has its medial arm slid between one endotl the main core' and the part' of the-coil 3 which extends around that core end;v

lilith the transformer thus arranged," itI willlbe obvioustrom Figs.' land 7' that theA secondary (or belleircuit) windingris disposed in the sarde wellielosed magnetic'eircuit Vwith"the'main winding'l an'dlinl clos'e inductive relation to the latter, therebyunaikv ingmy transformer quite efficienty for giving" a loud'alarm signal.

At the same time, the winding- 3,' which is in series with the electromagnet of the de` tent-releasing device` has a considerable portion infinduet-ive relation to the same main' transformer windinfrTand has another portion in inductive relation to the medial shank 162L of the auxiliary core. This shank 16n closer to the winding 3 'than the adjacent; shank 13b ot the main core' and the shankltla partly shields the winding3`iiron1 the inductive action of variations in' tlm;` throughfthe shank 13", asv will be) seentro'm Fig. 7, so'that the winding 3tisl`more largely influenced by the central shank 16"y ot the auxiliary' core than by the'endshank 13 et the main core. The' current in the'wiiiding 3 flows in"the'saine'direction around the exterior of the shanks 3a antl16,lieiice the prepondera-tingj inductive influence ot the shank 16a over the shank 13b augf'ments that of" the shanks and'13C onthey winding 3. For example, if' the magnetisme' influence of the current inthe main'winding 1 during onefha'lt cyclev of thealternations makes theV top ott the medialshank'lS of thel main'core portion a south pole, asinar'ked in Fig. 2, the' tops ot the lateral Shanks of this main core portions would be north poles. The auxiliary core portion has its medial shank parallel to. one of the saidv lateral `Shanks ofV the main core portion, but spaced from it byv a dielectric 18. Hence the magnetizing'of the lastnamed main core shank will induce an opposite magnetization in the medial shank of the auxiliary core portion, thus making the upper end of the latter shank a south pole and making the upper ends of the end shanks of the auxiliary core portion north poles, as marked in Fig. 5., Since the winding 3 passes in the same direction around the medial shanks of both core portions and since these both have their south poles si multaneously either at the upper or the lower ends. the variations in magnetic flux through these two medial Shanks. act `conjointly on lthe Winding 3. So also, since a part of this winding passes inside the lateral shanks of the auxiliary core, orei'ectively in a reverse direction from that around the medial shank of this core, the magnetic fluctuations in these lateral shanks also induce a currentow in the same direcf tion in the winding 3.

Consequently, I can secure an adequate Aefficiency for ,the generation of the clonposed within it in the older manner would.

heat to such an extent as to melt various insulating materials.

In practice, I have found it advantageous to dispose the secondary winding 2 between the third winding 3 and the `primary winding I. to this feature, nor to the details of the construction and assemblage above described, as many changes might obviously be made without departing either from the spirit of my invention or from the appended claims.

Neither do I wish to be limited to the ernployment of my invention in a transformer arranged for supplying current to a normally open as well as another and normally closed circuit, since my arrangement of the cores and of the windings l and 3 would obviously operate also if the winding 2 were omitted. So also, the current generated in the secondary winding 2 may be employed for other purposes in addition to the operation of an alarm controlled by current through the winding 3. For example, taps l2 might be run from the circuit of the winding 2, as indicated in dotted lines in Fig. 6, for operating ordinary house bell circuits,

However, I do not wish to be limitedV thus making my transformer furnish currents for the. regular door bells in addition to the burglar alarm circuit. I .claim as my invention: l'

' l." In a transformer,v a main corehaving three parallel shanks; an auxiliary core also having three parallel Shanks, and having its medial shank spaced from, but in Amagnetizable relation to, one lateral shank ofthe main core; and coil windings including a main winding extending around the medial shank of the main core inside the lateral Shanks of the main core, anda second windc ing extending around the medial shankof Y the auxiliary core and between that shank and the lateral `shanks of the auxiliary core,

the second windingalso having aportion extending around the medial shank of the main" corebetwe-en 'the latter shankand the other lateral shank of that core.

2. A transformer as per claim 1 in which the said portion of the second winding is disposed between the said other lateral shank of the main core and the main winding.

3. A transformer as per claim 1, in which the coil windings also include a secondary winding surrounding the main Winding and extending inside thevlateral Shanks of theV main core.

4. A transformer as per claim l, in which the coil windings also include a secondary winding surrounding the main winding and having a part disposed between the main winding and the said portion of the second winding.

c 5.,A transformer for supplying current from a supply circuit both to a normally closed circuit and to a normally open circuit, comprising a main core having three parallel shanks, an auxiliary core having a shank parallel to and spaced from one lateral shank of the main core; a supply circuit Y winding surrounding the medial shank of the main core, a normally open circuit winda ing surrounding the supply circuit winding, the saidl two windings both extending between the medial and the lateral shanks of the main core; and a normally closed circuit winding having one portion extending between the said open circuit windingl and the other lateral shank of the core, andhaving another portion extending outside the first4 named lateral shank and around the outer face of the said shank of the auxiliary core.V

6. In a voltage reducing transformer, a core including three parallel Shanks, a main winding and a secondary winding both extending around the medial shank of the core, i

and between the medial shank' and` both lateral shanks ofthe core; a third windingv extending around the main winding between the latter and one lateral shank of the core and extending` outside the other lateral shank of the core, and an auxiliary core having a part thereof disposed outside and `:spaced :from ,the said v`other lateral shank'Ar faildznsde thethrd Winding.

7. A transformenas perflalin ,6, in whicli the auxiliary corealso has other portions in inductive relation vtothe tliird .Winding and fdisposed-outside-the latter.

8. .v-Ina tiranformer, aanain coreofhol- 10M `reo tangulzu vertiqalosectionllavng an .added oentraletemneaijer to oneside of the oorzetlian.,to thejotliei side anV auxiliary core -`disposed 4at ,right .angles yto themain core, the y.Verticalsection of theauxiliaiy core in `@plane atrightangles kto:tlie ,aforesaid Ver :tical: seetionbeing U Witlianl added centraal shankfthe saidahank being adjacent to the KYAeai d i1st named sidefof the main core; a j,dielectric spaeingthe said shank from the `said .fir-stgnamed side ofthe main Core; a pair of Windingsfboth :extending yaround ,the fcen- 'tral stem of the fman coreaandzpassngbetween theqsaid .stem andtbotli ,sides ,of ,the

between .u the said V:Stern and [the Y Said oftlier SeldenQf'themaincore, andfextendlng outilcle YQJV'lhe combination with a transformer core including va l pair ,of panallel L Shanks, of .a pri'niarry Winding `andfa secondary Winding both extending between the ,two Shanks around tlielirst of tlie said Slianlm an auXli faiy Core including LAan auxiliauy eolie Shan-k disposed parallel: tobut spaced from thesee- -ond .of thea'foreeaid two Shanks, and ,a third AWinding' L. extending :around the oppQSitely directed faces of the saidiiist shank 'and ,th Asaid auxiliary core shank.

Sign-edfat Chicago, illinois, October 18th,

WILLIAM F. LEATHER. 

